Carrier, electrophotographic developer, and method of manufacturing carrier

Abstract

An object of the present invention is to provide a carrier low in specific gravity and less in both environmental fluctuation and change of the charge amount after aging, an electrophotographic developer using the carrier, and a method of manufacturing the carrier. To achieve the object, the carrier is manufactured by coating a core material composed of a magnetic component and a non-magnetic component with a resin, and the carrier is characterized in that water content is 200 ppm or less and cyclic siloxane content is 100 ppb or less. Further, an electrophotographic developer containing the carrier is provided.

What is claimed is: 
     
       1. A carrier which is a core material composed of a magnetic component and a non-magnetic component coated with a resin, characterized in that
 the carrier has water content of 200 ppm or less and cyclic siloxane content of 100 ppb or less. 
 
     
     
       2. The carrier according to  claim 1 , wherein
 the carrier has a volatile organic compound content of 1.5 ppm or less. 
 
     
     
       3. The carrier according to  claim 1 , wherein
 the carrier has a true specific gravity of 3.5 g/cm 3  or more and 4.5 g/cm 3  or less. 
 
     
     
       4. The carrier according to  claim 1 , wherein
 the magnetic component is a ferrite. 
 
     
     
       5. The carrier according to  claim 1 , wherein
 the non-magnetic component is a siloxane compound comprising one or more groups selected from methyl groups and phenyl groups. 
 
     
     
       6. The carrier according to  claim 5 , wherein
 the non-magnetic component is finished by curing a non-magnetic component composition without volatile organic solvents containing the siloxane compound having a mass average molecular weight of 150 to 10000. 
 
     
     
       7. The carrier according to  claim 1 , wherein
 the core material is composed of porous ferrite particles and the non-magnetic component filling the pores in the porous ferrite particles. 
 
     
     
       8. An electrophotographic developer containing the carrier according to  claim 1 .